the impact of drought on leaf area index (lai) over texas ling huang 12/04/2012
TRANSCRIPT
The Impact of Drought on Leaf Area Index (LAI) over Texas
Ling Huang12/04/2012
Background – Why LAI is concerned?
Leaf Area Index (LAI): one half the total leaf area per unit of ground area
Importance: critical parameter controlling many biological and physical processes involving vegetation
LAI is a key variable controlling ozone production!
LAI
Background – Why LAI is concerned?
NO NO2 sunlight
O2
Air O2
O(3P)
O3
VOC….RO2
RO
No ozone accumulation!!
Accumulation!
Biogenic Emission
s
Drought?
How LAI is affected by drought?
LAIBiogenic Emission
s
Data and Method2011 (drought) vs. 2010 (wet)MODIS LAI product (Moderate Resolution
Imaging Spectroradiometer) Area: TexasPeriod: May to September
Mosaic
Raw LAI
Apply QC mask
Scaling
Clip
Final LAI
Model Builder in ArcGIS
Temperature
Results – LAI distribution over Texas
Precipitation
Results – Statistical comparison
Results – geographical comparison
>0.75 No impact
LAI_2010
LAI_2011ratio LAI
0.5-0.75 Moderate
0.25-0.5 Significant
<0.25 Extreme
Impact of Drought
Results – Texas climate divisions
NCDC: 10 climate divisions in TexasSimilar characteristics: vegetation, temperature,
humidity, rainfall, seasonal weather changes
semi-arid savanna semi-arid savanna
semi-arid brushland and savanna
Sub-humid savannaand woodland
Sub-arid brushland
Transition Zone!
Conclusions
LAI Biogenic Emissions
Ozone concentration
s
1.
2. LAI
Temperature
Precipitation
3. LAIDrought
In July 2011, nearly 90% of areas saw the impact of
drought and over 50% were significantly affected.
4. Transition zones
5. GIS is an excellent tool to view the
impact of drought geographically.
6. Less Ozone Production,
especially in VOC-limited regions
Acknowledgements
Dr. MaidmentGonzalo Espinoza DávalosYosuke KimuraDr. Allen
Thank you!